Mate, I have to completely disagree. The reason Hazard isn't able to score more goals is because his finishing is comparatively poor with other top wingers (Robben, Ronaldo, Neymar, Bale, Griezmann in his early days). Even with Sanchez playing for Arsenal, he still registers far better performances and stats than Hazard (Past three seasons, all club competitions -> Sanchez: 64 goals and 41 assists, Hazard: 39 goals and 27 assists).
Chelsea have a very functional and systematic offense now... it's not "toss it to Hazard/Costa and let's see what they can do" any more. And Hazard has certainly recovered from his slump last season and is a solid player now. But I think it's fairly obvious from an objectional standpoint that Sanchez is on a pedestal above him (achieves more with less).
Like @Sun said, he's been consistently outshone on his own national team.
"27-year-old Gabon international Aubameyang has been linked with moves to the Premier League in the past a well as continental heavyweights PSG and Real Madrid.
According to the research, his age, position, contract status and traits make him the the most likely candidate to become the first in world-football to secure a £100m transfer." - b/r
Who do you think will be the first?